This patent document relates to optical communications, and related devices, systems and techniques, including optical communications based on Optical orthogonal frequency division multiplexing.
Optical orthogonal frequency division multiplexing (OOFDM) has actively been investigated due to its potential of electrical equalization to eliminate fiber chromatic dispersion (CD) and polarization mode dispersion (PMD). Besides, highly spectral efficiency makes it attractive for the future high capacity signal transmission. The optical OFDM system can be mainly classified into two types: coherent optical OFDM (CO-OFDM) system and direct-detected optical OFDM (DDO-OFDM) system. In general, CO-OFDM exhibits better performance in receiver sensitivity, spectral efficiency and robustness against polarization mode dispersion. However, the transmitter and receiver is more complex and expensive. In contrast, the DDO-OFDM system is much easy to be implemented, and it has the merit of the low cost.